The GP40 and GP40-2, Pinnacle of the Four-Axle Geeps

EMD originally began as the Electro-Motive Corporation and has its beginnings in 1922 being based out of Cleveland, Ohio building inexpensive motorcars. With the purchase of the company in 1930 by General Motor, and more resources at its disposal the company began developing the precursor of the modern-day diesel-electric road unit (cabs and road-switchers), the streamlined trainset, which consisted of a powered car permanently attached to a few coaches (usually two or three cars).

The most famous of these streamlined trainsets was the Burlington Zephyrs, a beautiful streamlined stainless steel creation (originally powered by Winton engines, which would also become a subsidiary of GM) that was extremely lightweight and fast. The original trainset, the Zephyr 9900, made headlines in 1934 when it completed a non-stop journey from Denver to Chicago in a little over 13 hours.

Because the power cars with these trainsets were permanently attached to the coaches EMC sought to design a locomotive free of this articulated setup but designed in such a manner that a railroad could still attach it to any passenger train and obtain the same, smooth streamlined look. This it did with the unveiling of the EA model in 1937, the first in a long line of passenger diesel locomotive designs that would come to be known as the E series.

Not surprisingly, soon after the EA unveiling the company decided to take things a step further and develop the first true diesel road unit, capable of pulling long freights in main line service. In 1939 it introduced the FT model (perhaps the key difference between the E and F series was that Fs rode on B-B trucks whereas Es rode on C-Cs and carried a noticeably longer carbody), the first in EMC’s F series and one of the most success diesel-electric designs of all time. The F series would go on to define American railroading for years and you can still see it in regular use today, over 60 years after it first debuted! The FT (which stood for Freight, Twenty-seven hundred horsepower) was a superb locomotive and although its 2,700 horsepower came from an A-B setup of a cab (A) and booster (B) units rated at 1,350 horsepower each, it was quickly loved by railroads for the efficiencies it held over steam such as its ruggedness and ease of maintenance.

The FT (which stood for Freight, Twenty-seven hundred horsepower) was a serious locomotive and although its 2,700 horsepower came from an A-B setup of cab (A) and booster (B) units rated at 1,350 horsepower each it would become embraced by the rail industry for the efficiencies it held over steam power as well as being rugged and easy to maintain.

Following the success of its cab units, EMD realized that there was a market to be made in the road-switchers, which at the time was mostly dominated by Alco with its RS series. Its first attempt at this type of locomotive, which gave the train crews both excellent vision all around the locomotive for switching and local service as well as enough horsepower to be used in main line operations, was the BL2. Although unsuccessful from a sales standpoint the BL2 was really a mere stepping-stone for its next model, the GP series (meaning General Purpose).

The GP40 and GP40-2 production run lasted over twenty years beginning in 1965 and ceasing in 1987 (the GP40 was last produced in 1971). The units themselves were not that different from GP38s and GP38-2s except that they included some newer technologies; an extra radiator fan, turbocharger stack and an extra 1,000 hp (rated at 3,000 hp over the GP38 series 2,000 hp). The GP40 also included features already now common on earlier models such as dynamic braking (a system for temporarily employing traction motors as generators and using the resulting electromotive force to slow the train), and an airtight hood that kept out dust, dirt and other particles from reaching internal components. The "Dash 2" model is distinguished from the original because of its further upgrades which included things like a newer type of traction motor blower duct, a modular electronic cabinet system and bolted battery box access doors. Essentially, as with all EMD “Dash” models, GP40-2s basically include upgraded electronics and technologies over the original design.

Also, the GP40 and GP40-2 models were the pinnacle of EMD’s four-axle locomotives in several ways. First, the design was EMD’s most successful second-generation locomotive. Combined GP40s and GP40-2s sold over 2,300 units with the GP40 selling some 1,200+ units and the GP40-2 slightly less at just over 1,100. Second, the model effectively ended production of four-axle power as railroads began to order more and more six-axle units because of their added traction and weight distribution (meaning that with an extra two axles the locomotive’s weight was more evenly distributed over the rails causing less wear on them). Later GP50 and GP60 models were produced but were only marginally success compared to the GP40 and early series. Today, virtually all new locomotives ordered are of the C-C, six-axle variety save for switchers or light duty units.

In any event, these Geeps remain as common as railroad spikes out on main lines across the country and you can spot them virtually anywhere as they carry all of the classic EMD features. Of note are a few differing models which included the GP40P built for NJ Transit in commuter service (an added steam generator for passengers) and the GP40-2W, built for Canadian National that included the wide cab commonly used in Canada.

The GP40 and GP40-2 models, along with the GP38 and GP38-2, were EMD’s most successful second-generation Geeps and like earlier models fit exactly what railroads were looking for in terms of horsepower while also featuring the manufacturers’ excellence in quality and reliability. In any event, be on the lookout for GP40s because there are still hundreds roaming around out there!

For more information on the GP40 series consider one (or both) of the books below. Mike Schafer’s Vintage Diesel Locomotives looks at virtually all of the classic builders and models from Alco PAs to early EMD Geeps. If you’re interested in classic EMDs, or diesels in general, this book gives an excellent general history of both.

Also, Brian Solomon’s The American Diesel Locomotive also studies many of the same diesel models and builders as Mr. Schafer’s publication although at nearly twice the size the book goes into a bit more detail than Vintage Diesel Locomotives and also covers newer models. All in all, though, both books are a great read and you shouldn’t be disappointed with them, not to mention that they are loaded with photos (many in color)!